Much like your car Outdoor Power Equipment too has engine numbers, model numbers, type numbers etc. and spares need to be ordered using these numbers to find the correct spare.
You can basically use two methods of identifying the correct parts:
1. You could complete the request form by entering the basic information and request a quote by submitting the form, or
2. You could use a "PartTree" to identify the part you need and then enter the request form with specific information on the part you need.